Berberine reduces inflammation of human dental pulp fibroblast via miR-21/KBTBD7 axis.

OBJECTIVE

This study is to investigate the effect and underlying mechanisms of berberine (BBR) on the proliferation and inflammatory levels of lipopolysaccharide induced human dental pulp fibroblast (LPS-HDPF).

METHODS

Different concentrations of LPS were used to induce inflammatory response of HDPF. Cell proliferation was observed in BBR treated HDPF after transfection of miR-21 mimic, miR-21 inhibitor or sh-kBTBD7 plasmids and their negative controls. ELISA was employed to detect the expressions of inflammation related cytokines. Real-time quantitative RT-PCR was applied to estimate the expressions of miR-21 and KBTBD7. KBTBD7 expression was detected by Immunocytochemistry. Western blot analysis showed the protein levels of KBTBD7, Phospho-IKKα/β, IKKβ, Phospho-NF-κB p65, NF-κB p65, and IκBα. Luciferase reporter gene assay was used to determine the interaction between miR-21 and KBTBD7.

RESULTS

LPS could promote inflammatory response in HDPF. Down-regulated miR-21 and up-regulated KBTBD7 were found in LPS-HDPF. BBR (25 uM) treatment in LPS-HDPF could ameliorate cell inflammatory response, presented by reduced expressions of IL-1β, IL-6 and TNF-α, as well as enhanced cell proliferation and miR-21 expression. Moreover, miR-21 negatively targets KBTBD7. Over-expression of miR-21 or silencing of KBTBD7 could enhance the protective role of BBR on LPS-HDPF by inhibiting inflammatory response and promoting cell proliferation. Transfection of miR-21 overexpression or KBTBD7 silencing in BBR treated LPS-HDPF could inhibit activation of NF-κB signal pathway.

CONCLUSION

Evidence in this study suggested that BBR mediates LPS induced inflammation in HDPF via miR-21/KBTBD7 axis to regulate NF-κB signal pathway, which may provide theoretical basis for BBR in prevention of pulpitis.